From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5209825782D for ; Wed, 20 May 2026 00:50:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779238236; cv=none; b=NJBv3bqxCDxqmBJS4ObxWntsVk9q0lBMrAM/sXloz6QYBUzrh1vFhSLo0trd4lYS8UEV8WD0l6Gemh+Uir9jlyzDza0u00+FUaeTHnGjFQy2aMtGzgmW3MoW99ZGjXHLjdfKnIDU++uR0LScMMyu0r9kJe1pyt2g+Acuu26a3WM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779238236; c=relaxed/simple; bh=Opf0c/atUxequfa4xWIBLNmw50G7mwnJpzYXl6QYRmo=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=ofSKMD8m129onqGaVpTiT6c+4wGKDpKtpZIwJsjK5ROSESeSluFxbuVnSeDUmwpJJeXqNVcy9UegALdX89bAGwP/HX4mqKre2vTkHQwXz/GRzmOSK3BcpmOmxzskUQHDZci+MdFWmFLwOyQXE1l/KLYLA4c6JqQL5hCeOwhN5bo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=casper.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=iXEEAHto; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=casper.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="iXEEAHto" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Opf0c/atUxequfa4xWIBLNmw50G7mwnJpzYXl6QYRmo=; b=iXEEAHto/nm/g0NRocdRlxRfTI MpD5P9I6fBt81M5tkxRnEXN2k0njr888zukWQZy/WcTMGsgcFWpajY2pD9x3klDbeoMlQGwLZWLwG +6W77hvb8eArdSJ4TIUqr73gAbNyCrEbS0E+W6f7COzGHzc6mHO7w+ColkYHteuLizatjmvG+/MDQ pyFB8yGPSKnHDLTmU4+C30C58XcCyubk2slZfzy1aaJbsLbAc7VeLTKIfq5e6TkKmOMZKaWg9hrDI vymlG0c06LsmI0yQoN4VZ6hTWpQ/J8hX6hvBwQaGExFSszLsLazKwaWiouh6Eu/95lMB7NzXyPJZi DWRmWq2g==; Received: from [172.31.31.148] (helo=u09cd745991455d.lumleys.internal) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wPV8d-00000006Yhs-43Ty; Wed, 20 May 2026 00:50:20 +0000 Message-ID: Subject: Re: [RFC PATCH 1/4] timekeeping: Remove xtime_remainder from ntp_error accumulation From: David Woodhouse To: John Stultz Cc: Miroslav Lichvar , Richard Cochran , Wen Gu , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Thomas Gleixner , Stephen Boyd , Anna-Maria Behnsen , Frederic Weisbecker , Shuah Khan , Peter Zijlstra , Thomas =?ISO-8859-1?Q?Wei=DFschuh?= , Arnd Bergmann , linux-kernel@vger.kernel.org Date: Wed, 20 May 2026 01:50:19 +0100 In-Reply-To: References: <20260513210157.3410814-1-dwmw2@infradead.org> <20260513210157.3410814-2-dwmw2@infradead.org> <5b8a8117a5c45482a515d9fcf026b2a1ae7c5176.camel@infradead.org> <112efe3ec75c3a0bf3ea9d53034a7dea9bd553c7.camel@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-bmEfIO0Z76f0Sukxzqab" User-Agent: Evolution 3.52.3-0ubuntu1.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html --=-bmEfIO0Z76f0Sukxzqab Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2026-05-19 at 17:32 -0700, John Stultz wrote: > On Tue, May 19, 2026 at 3:20=E2=80=AFPM David Woodhouse > wrote: > >=20 > > On Tue, 2026-05-19 at 14:54 -0700, John Stultz wrote: > > >=20 > > > Its a nice analogy. Though if you're going to use it in your > > > commit > > > messages, it might be good to also add a comment to the > > > timekeeping_adjustment() logic so there is an clear anchor to the > > > code > > > for folks who might not be as familiar with the detail. > > >=20 > > >=20 > > > > > Also I'm not sure its very clear what you mean by > > > > > "monotonicity clawback". > > > >=20 > > > > This is the offset applied by timekeeping_apply_adjustment() in > > > > order > > > > to ensure that the observed xtime remains monotonic when the > > > > dithering > > > > switches back from 'mult+1' to 'mult' and a consumer may have > > > > seen a > > > > 'later' time than it's about to set in {cycle_last,mult}. > > > >=20 > > >=20 > > > This one I find less clarifying, but I do recognize "adjustments > > > to > > > the base xtime_nsec made when adjusting the multiplier due to > > > unaccumulated cycles" is a mouthful. > > >=20 > > > The "xtime_nsec adjustment in timekeeping_apply_adjustment()" is > > > probably easier/clearer? > >=20 > > How's this... > >=20 > > # Linux Timekeeping: Tick-Based Clock Discipline >=20 > So, I'm guessing given how fast you were to create this and how > verbose it is, it was AI generated? (Apologies if I'm wrong here!) It was originally, yes. But it wasn't that fast; I've had it open in emacs for a week or so now. I had the AI write it for me so that I could sanity-check it and refine my own understanding. I trust the AI about as far as I can throw it. > If so, do remember to use the Assisted-by tag. Ack. > I'll try to find some time to carefully review it, but while I > appreciate the benefit of having a tool help write this, I'm not super > excited about externalizing the cost of the review onto others. > As careful review and feedback of an individuals work feels like > investing in that collaborative effort, but doing the same for AI > generated output just feels like a chore. Oh, absolutely! I have actually done the first week's worth of saying "no, that's complete horseshit. Tell me the truth" to it, as well as refining the flow to make it read more coherently :) --=-bmEfIO0Z76f0Sukxzqab Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCD9Aw ggSOMIIDdqADAgECAhAOmiw0ECVD4cWj5DqVrT9PMA0GCSqGSIb3DQEBCwUAMGUxCzAJBgNVBAYT AlVTMRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5jb20xJDAi BgNVBAMTG0RpZ2lDZXJ0IEFzc3VyZWQgSUQgUm9vdCBDQTAeFw0yNDAxMzAwMDAwMDBaFw0zMTEx MDkyMzU5NTlaMEExCzAJBgNVBAYTAkFVMRAwDgYDVQQKEwdWZXJva2V5MSAwHgYDVQQDExdWZXJv a2V5IFNlY3VyZSBFbWFpbCBHMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMjvgLKj jfhCFqxYyRiW8g3cNFAvltDbK5AzcOaR7yVzVGadr4YcCVxjKrEJOgi7WEOH8rUgCNB5cTD8N/Et GfZI+LGqSv0YtNa54T9D1AWJy08ZKkWvfGGIXN9UFAPMJ6OLLH/UUEgFa+7KlrEvMUupDFGnnR06 aDJAwtycb8yXtILj+TvfhLFhafxroXrflspavejQkEiHjNjtHnwbZ+o43g0/yxjwnarGI3kgcak7 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